I have modified 2 LA 46s by simply but CAREFULLY filing the transfer ports with a flat needle file, measuring the height first with calipers and then removing 25 thousandths leaving the roof angle at 90 degrees and the same height all the way across. This is exactly what Derek Pickard was doing and I found this mod in an article he produced back in the..well back a while ago. There is minimal power loss but that was not an issue FOR ME. The motor now runs in a solid 4 and just breaks at the tops lightly (depending on prop, compr, venturi size etc) but the real deal here is...it does this EVERY time. Derek even states in his article that "right every time counts a lot". I am NOT saying the stock motor doesn't run right every time for everybody...it just didn't FOR ME. As far as stunt timing for Brian's P/L sets as long as we don't expect a wet 2 run and more of a 4/2 run I know I would be VERY pleased as my hack at the motor produced exactly the results I wanted. His "mods" no doubt would be an even greater improvement. I can only attest to modified timing. Mike Scott, Doug Moon and Chris Rigotti can attest to the motor runs i am getting on this motor....consistent is the best word I think. Again, not that others have not gotten consistent runs on a stock motor, I just didn't. NOW...FUEL CONSUMPTION!!! That's the real caveat...stock I could do the pattern on 3.25 to 3.5 ozs of 5/22 Powermaster...that is amazing to me...a pattern with 10 laps to spare on a .46 motor on 3.5 ozs pulling a 48 oz Cardinal!!! Incredible. Modified motor uses 5 ozs....every bit of it, same fuel (with 1 head shim). Just my 2 cents...if Brian makes these i will buy several for all, well not all, I would leave some stock, my 6 LA46s.